碧云天，黃花地，西風緊，北雁南飛。這四句詩句出自唐代詩人杜甫的《登高》一詩，形容了登高遠眺所見的景象。碧云天指的是天空中晴朗的藍天，黃花地則是指山間金黃的花海。西風緊則表明風勢較緊，北雁南飛則指的是秋季南遷的候鳥。這四句詩句通過形象生動的描寫，表現(xiàn)出大自然的壯麗和景色的美麗。

The four phrases "碧云天，黃花地，西風緊，北雁南飛" come from a poem by the Tang Dynasty poet Du Fu titled "Ascending Heights". They describe the scenery seen when one is at a high altitude. "碧云天" refers to the clear blue sky, "黃花地" describes the golden flowers in the mountains, "西風緊" indicates strong winds blowing from the west, and "北雁南飛" represents the migratory birds flying south in autumn. Through vivid descriptions, these four phrases depict the grandeur and beauty of nature.